Systems, methods, and apparatus for sealing a bucket dovetail in a turbine

Abstract

Certain embodiments of the invention may include systems methods, and apparatus for sealing a bucket dovetail in a turbine. According to an example embodiment of the invention, a method is provided for sealing a gap between a bucket dovetail and a rotor wheel slot. The method can include providing a bucket tab associated with a bucket dovetail, wherein the bucket tab is configured to accept a seal tab; configuring the bucket tab and the seal tab to engage at least one dimension upon insertion of the seal tab into the bucket tab; and sealing a gap between the bucket dovetail and a rotor wheel slot with the seal tab; wherein at least a portion of the seal tab changes as a function of temperature for further sealing gap between the bucket dovetail and the rotor wheel slot.

What is claimed is: 
     
       1. A method for sealing a gap between a bucket dovetail and a rotor wheel slot, comprising:
 providing a bucket tab associated with a bucket dovetail, wherein the bucket tab is configured to accept a seal tab, the seal tab having a spring deformable tab and a non-deformable portion, wherein the spring deformable tab has a greater thickness than a thickness of the non-deformable portion; 
 configuring the bucket tab and the seal tab to engage at least one dimension upon insertion of the seal tab into the bucket tab by defining a slot with at least a first section and a second section in the bucket tab, wherein the second section comprises a slot width greater than a slot width associated with the first section, and the spring deformable tab of the seal tab is operable to engage with and be retained in the second section of the bucket tab; and 
 sealing a gap between the bucket dovetail and a rotor wheel slot with the seal tab by contacting the rotor wheel slot with the seal tab; wherein at least a portion of the seal tab changes as a function of temperature for further sealing gap between the bucket dovetail and the rotor wheel slot. 
 
     
     
       2. The method of  claim 1 , further comprising coating at least a portion of the seal tab with a sacrificial layer for providing gap conformity between the seal tab and the rotor wheel slot. 
     
     
       3. The method of  claim 2 , wherein providing gap conformity comprises abrading, by at least a portion of the rotor wheel slot, at least a portion of the sacrificial layer from the seal tab during operation. 
     
     
       4. The method of  claim 1 , wherein at least a portion of the seal tab changes as a function of temperature by expanding via a material having a coefficient of thermal expansion greater than about 0.000016 length per length per degree Celsius. 
     
     
       5. The method of  claim 1 , wherein modifying the bucket tab to accept the seal tab comprises forming a slot in the bucket tab with a slot width corresponding to an approximate body thickness of bucket tab. 
     
     
       6. A system comprising:
 a turbine comprising:
 a rotor; 
 one or more rotor wheels connected to the rotor, wherein the one or more rotor wheels comprise one or more rotor wheel slots; 
 one or more buckets each comprising a bucket dovetail; 
 one or more bucket tabs associated with each bucket dovetail, wherein the one or more bucket tabs comprise a slot having at least a first section and a second section, wherein the second section comprises a slot width greater that a width associated with the first section; and 
 one or more seal tabs comprising a spring deformable tab, the one or more seal tabs configured for sealing a gap between the bucket dovetail and the rotor wheel slot by contacting the rotor wheel slot with the one or more seal tabs, the one or more seal tabs further configured to engage the one or more bucket tabs upon insertion of the one or more seal tabs into the one or more bucket tabs, wherein the spring deformable tab is operable to engage with and be retained in the second section of the bucket tab. 
 
 
     
     
       7. The system of  claim 6 , wherein the one or more seal tabs are further configured to expand as a function of temperature. 
     
     
       8. The system of  claim 6  wherein the one or more bucket dovetails are removeably attachable to the one or more rotor wheels by insertion of the bucket dovetail into the one or more rotor wheel slots. 
     
     
       9. The system of  claim 6 , wherein the one or more seal tabs comprise a sacrificial layer coating for providing gap conformity between the one or more seal tabs and the rotor wheel slot. 
     
     
       10. The system of  claim 6 , wherein the one or more bucket tabs comprise a slot width, the slot width corresponding to an approximate body thickness of the one or more seal tabs. 
     
     
       11. An apparatus for sealing a gap between a bucket dovetail and a rotor wheel slot in a turbine, the apparatus comprising:
 one or more bucket tabs associated with a bucket dovetail, the one or more bucket tabs comprising a slot having at least a first section and a second section, wherein the second section comprises a slot width greater that a width associated with the first section; and 
 one or more seal tabs comprising a spring deformable tab operable to engage with and be retained in the second section of the bucket tab, the one or more seal tabs configured for sealing a gap between the bucket dovetail and a rotor wheel slot and further configured to engage the one or more bucket tabs upon insertion of the one or more seal tabs into the one or more bucket tabs, wherein the one or more seal tabs seal the gap between the bucket dovetail and the rotor wheel slot by contacting the rotor wheel slot with the one or more seal tabs. 
 
     
     
       12. The apparatus of  claim 11 , wherein the one or more seal tabs are further configured to expand as a function of temperature. 
     
     
       13. The apparatus of  claim 12 , wherein the one or more bucket tabs comprise a slot width, the slot width corresponding to an approximate body thickness of the one or more seal tabs. 
     
     
       14. The apparatus of  claim 11 , wherein the one or more seal tabs comprise a sacrificial layer coating for providing gap conformity between the one or more seal tabs and the rotor wheel slot.